Are small changes in serum creatinine an important risk factor?

Abstract

PURPOSE OF REVIEW: Serum creatinine levels are strongly associated with longitudinal risk for cardiovascular disease and mortality. Recent studies addressed whether worsening renal function - defined by small increases in creatinine - is independently associated with adverse outcomes. This review evaluates the recent literature on worsened renal function as an independent risk factor. RECENT FINDINGS: Studies have evaluated worsening renal function as a predictor of cardiovascular outcomes and mortality in three settings: cardiac surgery patients, hospitalized heart failure patients, and ambulatory coronary artery disease patients. Small creatinine changes following cardiac surgery were strongly associated with mortality risk. One study found a J-shaped association between 48 h post surgery creatinine change and 30-day mortality risk. Compared with patients with creatinine decreases of 0-0.3 mg/dl, patients with creatinine increases less than 0.5 mg/dl had a twofold adjusted mortality risk and those with creatinine increases of at least 0.5 mg/dl had a nearly sixfold mortality risk; surprisingly those with decreases over 0.3 mg/dl had a twofold adjusted risk. Worsening renal function was also a strong predictor of mortality for hospitalized heart failure patients independent of baseline creatinine; the magnitude of creatinine rise appeared to be linearly associated with mortality risk. However, one study found no independent association between worsening renal function and cardiovascular or mortality risk over longer follow-up. SUMMARY: Acute elevations in serum creatinine had a linear association with increased risk for adverse outcomes among patients hospitalized for cardiac surgery or heart failure. Future studies should determine interventions to prevent and treat in-hospital worsening renal function to reduce the risk for adverse outcomes.